It also sucks out contrast and color saturation. Most diving lights are LED these days, and manufacturers go for "brightness" rather than accurate color renditi

It also sucks out contrast and color saturation. Most diving lights are LED these days, and manufacturers go for "brightness" rather than accurate color rendition, so the blue in these cool white inaccurately color rendering LEDs only adds to the problem. But I wonder if a diving photographer zagged instead, and used a bright but very warm, sub 3000K High CRI light source if the problem could be mitigated, reducing the temptation of digital color monkeying. Hard to find old film underwater images online shot with tungsten filament-burning incan light sources, but I would bet my salt that those images looked better and more color-accurate than anything a modern DSLR and post-color processing can produce.